Experimental parser: add dfa path iterator

tools/lexer_generator/generator.py

 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 123 matching lines @@
   parser.add_argument('--code')
   parser.add_argument('--encoding', default='latin1')
   parser.add_argument('--no-optimize-default', action='store_true')
   parser.add_argument('--no-minimize-default', action='store_true')
   parser.add_argument('--no-verify-default', action='store_true')
   parser.add_argument('--no-inline', action='store_true')
   parser.add_argument('--verbose', action='store_true')
   parser.add_argument('--debug-code', action='store_true')
   parser.add_argument('--profile', action='store_true')
   parser.add_argument('--rule-html')
+  parser.add_argument('--count-paths', action='store_true')
   args = parser.parse_args()
 
   minimize_default = not args.no_minimize_default
   verbose = args.verbose
 
   if args.profile:
     profiler = start_profiling()
 
   re_file = args.re
   if verbose:
     print "parsing %s" % re_file
   with open(re_file, 'r') as f:
     rule_processor = RuleProcessor(f.read(), args.encoding)
 
   if not args.no_optimize_default:
     rule_processor.default_automata().optimize_dfa(log = args.verbose)
 
   if minimize_default:
     if args.no_verify_default:
       DfaMinimizer.set_verify(False)
     dfa = rule_processor.default_automata().dfa()
     mdfa = rule_processor.default_automata().minimal_dfa()
     if verbose:
       print "nodes reduced from %s to %s" % (
         dfa.node_count(), mdfa.node_count())
     DfaMinimizer.set_verify(True)
 
+  if args.count_paths:
+    path_count = 0
+    print 'counting'
+    for path in rule_processor.default_automata().minimal_dfa().path_iter():
+      path_count += 1
+    print 'done', path_count
+
   html_file = args.html
   if html_file:
     html = generate_html(
       rule_processor, minimize_default, not args.no_merge_html)
     with open(args.html, 'w') as f:
       f.write(html)
       if verbose:
         print "wrote html to %s" % html_file
 
   rule_html_file = args.rule_html
@@ skipping 17 matching lines @@
       if verbose:
         print "wrote code to %s" % code_file
 
   input_file = args.input
   if input_file:
     with open(input_file, 'r') as f:
       lex(rule_processor, f.read())
 
   if args.profile:
     stop_profiling(profiler)